Heat oil in a saucepan over medium-low heat. Add onion and garlic and sauté until soft, 3-4 minutes. Slowly add the chicken broth, tomato sauce and chipotle adobo sauce and bring to a boil. Add cilantro and remove from heat. Pour into crock pot.
Add the drained beans, diced tomatoes, corn, cumin, oregano and stir. Add the chicken breasts; cover and cook on low heat for 4-6 hours.
Remove chicken and shred with two forks. Add chicken back into the soup, adjust salt and cumin to taste. Serve in bowls and top with cheese, avocado, scallions and cilantro. Also great with sour cream or crushed tortilla chips.